According to online statistics, the demand of 10kV motor is larger than that of 6kV motor, so it is not unreasonable to think about it carefully. In recent years, with the implementation of energy-saving policy, the domestic power grid has been upgraded to reduce line losses, and industrial and mining enterprises have chosen medium-sized 10kV motors instead of 6kV motors to reduce distribution investment, so the demand for medium-sized 10kV motors has increased greatly.
There is a reason why customers choose 10kV motors.
One of the technical difficulties of 10KV motor is the turn-to-turn insulation of stator coil. Because the wires are often thin, it is difficult to wrap mica tape in hand or machine. The film winding itself is used as turn-to-turn insulation, which has poor corona resistance. The turn-to-turn fault accounts for a large proportion of high-voltage motor faults, and the reliability of turn-to-turn insulation has attracted more and more attention. Some users even specify mica as the high-voltage motor with turn-to-turn insulation.
Winding wire is an important kind of winding wire. In large and medium-sized winding wires, when the heat resistance level is high and the mechanical strength is high, glass-covered wires are used, and appropriate adhesive paint is used during manufacturing.
The measures taken by foreign countries in this regard are the extensive use of mica winding. In recent years, the research work of mica powder belt turn-to-turn insulation has also been carried out in China. Some electromagnetic wire factories have also successfully developed mica winding wires with different structures with the assistance of insulation materials factories and motor factories. At present, many motor factories are applying and popularizing them.
Among the winding wires, paper winding still occupies a considerable position, which is mainly used in oil-immersed transformers. The oil-paper insulation formed at this time has excellent dielectric properties, low price and long service life. In recent years, film winding has developed rapidly, mainly including polyester film and polyimide film winding, mica tape package for wind turbines and high-voltage motors, polyester-imide film winding copper flat wire and so on.
It is imperative to improve the insulation performance of electromagnetic wire
Most of the faults and damages of rotating electric machines are caused by the damage of winding insulation, of which the turn-to-turn insulation of windings accounts for about 50%, and the consequences will be serious once it is damaged. Inter-turn insulation short circuit is basically caused by the fact that the inter-turn impulse voltage of the motor exceeds the working voltage of inter-turn insulation of some windings under various overvoltage, some of which are caused by mechanical damage of coils and windings in the manufacturing process, and some of which are caused by partial discharge caused by internal gaps of high-voltage motor windings and corona corrosion of high-voltage windings. The damage caused by the above factors is directly or indirectly related to the performance of the winding wire used in the motor. With the upgrading of rotating motors and the needs of various special motors and high-temperature resistant motors, it is imperative to develop new winding wires.